Nucleon in a periodic magnetic field: Finite-volume aspects

The paper presents an extension and a refinement of our previous work on the extraction of the doubly virtual forward Compton scattering amplitude on the lattice by using the background field technique, Phys. Rev. D 95, 031502 (2017) (arXiv:1610.05545). The zero frequency limit for the periodic background field is discussed, in which the well-known result is reproduced. Further, an upper limit for the magnitude of the external field is established for which the perturbative treatment is still possible. Finally, the framework is set for the evaluation of the finite-volume corrections allowing for the analysis of upcoming lattice results.Comment: 42 pages, 5 figures; version accepted for publication in Physical Review

Nucleon in a periodic magnetic field

The energy shift of a nucleon in a static periodic magnetic field is evaluated at second order in the external field strength in perturbation theory. It is shown that the measurement of this energy shift on the lattice allows one to determine the unknown subtraction function in the forward doubly virtual Compton scattering amplitude. The limits of applicability of the obtained formula for the energy shift are discussed.Comment: The explicit factor $e$ is restored in the equations. The conclusions are unchange

On linear coupling of acoustic and cyclotron waves in plasma flows

It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are exactly similar to the ones describing coupling of sound waves with internal gravity waves [Rogava & Mahajan: Phys. Rev. E vol.55, 1185 (1997)] in neutral fluid flows. Using another noteworthy quantum mechanical analogy we calculate transformation coefficients and give fully analytic, quantitative description of the coupling efficiency for flows with low shearing rates.Comment: 5 pages, no figures. Submitted to "Physics of Plasmas

Hyperhomocysteinemia: related genetic diseases and congenital defects, abnormal DNA methylation and newborn screening issues

Homocysteine, a sulfur-containing amino acid derived from the methionine metabolism, is located at the branch point of two pathways of the methionine cycle, i.e. remethylation and transsulfuration. Gene abnormalities in the enzymes catalyzing reactions in both pathways lead to hyperhomocysteinemia. Hyperhomocysteinemia is associated with increased risk for congenital disorders, including neural tube closure defects, heart defects, cleft lip/palate, Down syndrome, and multi-system abnormalities in adults. Since hyperhomocysteinemia is known to affect the extent of DNA methylation, it is likely that abnormal DNA methylation during embryogenesis, may be a pathogenic factor for these congenital disorders. In this review we highlight the importance of homocysteinemia by describing the genes encoding for enzymes of homocysteine metabolism relevant to the clinical practice, especially cystathionine-β-synthase and methylenetetrahydrofolate reductase mutations, and the impairment of related metabolites levels. Moreover, a possible correlation between hyperhomocysteine and congenital disorders through the involvement of abnormal DNA methylation during embryogenesis is discussed. Finally, the relevance of present and future diagnostic tools such as tandem mass spectrometry and next generation sequencing in newborn screening is highlighted

Virtual Reality of Historical Places in North Sulawesi

Sulawesi Utara adalah salah satu provinsi di Indonesia yang memiliki banyak tempat menarik untuk dikunjungi, seperti wisata alam, kuliner dan tempat-tempat bersejarah. Presentasi informasi yang mudah dan menarik sangat penting untuk atraksi wisata di SulawesiUtara. Penyajian informasi yang menarik dapat menarik minat wisatawan mancanegara maupun lokal untuk berkungjung di Sulawesi Utara. Virtual Reality menjadi salah satu teknologi yang dapat memberikan pengalaman baru dalam melakukan eksplorasi suatu tempatsecara digital dengan sangat atraktif. Oleh karena itu, tujuan dari penelitian ini adalah mengembangkan sebuah aplikasi yang dapat memberikan informasi tentang tujuh tempat bersejarah di Sulawesi Utara dengan menggunakan teknologi virtual reality, terutama teknikfotografi yang merupakan teknik untuk menampilkan gambar dengan sudut pandang 360 derajat. Aplikasi ini dirancang menggunakan metode Prototyping sebagai model proses. Unity 3D digunakan dalam penelitian ini untuk membangun aplikasi dan antarmuka dan memungkinkan untuk dapat di jalankan di berbagai operating system. Aplikasi ini dibuat menggunakan bahasa pemrograman C #. Dalam penelitian ini dibahas mulai dari proses desain, pengambilan gambar dengan teknik Immersive, hingga menghasilkan aplikasi yang siap digunakan

Random Graph-Homomorphisms and Logarithmic Degree

A graph homomorphism between two graphs is a map from the vertex set of one graph to the vertex set of the other graph, that maps edges to edges. In this note we study the range of a uniformly chosen homomorphism from a graph G to the infinite line Z. It is shown that if the maximal degree of G is `sub-logarithmic', then the range of such a homomorphism is super-constant. Furthermore, some examples are provided, suggesting that perhaps for graphs with super-logarithmic degree, the range of a typical homomorphism is bounded. In particular, a sharp transition is shown for a specific family of graphs C_{n,k} (which is the tensor product of the n-cycle and a complete graph, with self-loops, of size k). That is, given any function psi(n) tending to infinity, the range of a typical homomorphism of C_{n,k} is super-constant for k = 2 log(n) - psi(n), and is 3 for k = 2 log(n) + psi(n)

Impairment of methyl cycle affects mitochondrial methyl availability and glutathione level in Down's Sindrome

In Down's syndrome there is evidence that increased gene expression coding for specific cystathionine beta-synthase translates directly into biochemical aberrations, which result in a biochemical and metabolic imbalance of the methyl status. This event is destined to impact mitochondrial function since methylation is a necessary event in mitochondria and relies on the availability and uptake of the methyl donor S-adenosylmethionine. Indeed mitochondrial dysfunctions have been widely described in Down's syndrome, but they have never been correlated to a possible mitochondrial methyl unbalance. In the present study we find that the mitochondrial levels of S-adenosylmethionine are reduced in Down's syndrome compared to control cells demonstrating the effect of the methyl unbalance on mitochondria. The possible role of methylation in mitochondria is discussed and some preliminary results on a possible methylation target are presented

Impairment of methyl cycle affects mitochondrial methyl availability and glutathione level in Down's Sindrome

In Down's syndrome there is evidence that increased gene expression coding for specific cystathionine beta-synthase translates directly into biochemical aberrations, which result in a biochemical and metabolic imbalance of the methyl status. This event is destined to impact mitochondrial function since methylation is a necessary event in mitochondria and relies on the availability and uptake of the methyl donor S-adenosylmethionine. Indeed mitochondrial dysfunctions have been widely described in Down's syndrome, but they have never been correlated to a possible mitochondrial methyl unbalance. In the present study we find that the mitochondrial levels of S-adenosylmethionine are reduced in Down's syndrome compared to control cells demonstrating the effect of the methyl unbalance on mitochondria. The possible role of methylation in mitochondria is discussed and some preliminary results on a possible methylation target are presented

Crohn's-like ileo-colitis in patients affected by glycogen storage disease Ib: Two years' follow-up of patients with a wide spectrum of gastrointestinal signs

Aim: To investigate the presence of inflammatory bowel disease (IBD) and to evaluate the progression of bowel involvement after two years' follow-up in seven patients affected by glycogen storage disease type Ib (GSDIb). Methods: Seven patients (5F, 2M, aged 4.5-20.6 y) entered the study. Bowel involvement was evaluated by ileocolonoscopy and specific IBD serologic markers. To evaluate disease activity, Paediatric Crohn's Disease Activity Index (PCDAI), terminal ileum wall thickness detected at ultrasonography (US), 99mTechnetium labelled autologous White Cell Scan (Tc-WCS) and barium meal with follow-through were investigated. Results: Ileocolonoscopy and histology examination revealed variable degrees of bowel involvement in all patients. The results of serologic markers were indicative of a Crohn's-like ileocolitis. US and Tc-WCS, could clearly define patients with severe inflammatory involvement, but failed to identify all patients with mild to moderate disease. For the most severely affected patients, anti-inflammatory agents and steroids were prescribed, whereas nutritional therapy with polymeric formula and antibiotics were assumed by two other patients and antibiotics only by one patient. Granulocyte colony-stimulating factor (G-CSF) was prescribed to all patients. Ileocolonoscopy and histology data improved in all patients. The assumption of G-CSF and/or gastric drip feeding (g.d.f.) was inversely associated with the PCDAI results (p < 0.05). Conclusion: IBD is common in patients affected by GSDIb independently of the severity of gastrointestinal signs and symptoms. Different therapeutic approaches can be used according to the severity of IBD. G-CSF treatment and g.d.f. can be protective factors for IBD

Aplikasi Virtual Reality Pengenalan Kerangka Tubuh Manusia Berbasis Android

Penelitian ini menghasilkan Aplikasi kerangka tubuh manusia yang perancangannya dalam bentuk tiga dimensi (3D) dan pada penelitian ini menampilkan tulang – tulang manusia dari kepala, badan dan anggota gerak. Aplikasi ini digunakan untuk sarana pengenalan dalam bentuk virtual. Peneliti memanfaatkan teknologi komputer grafik yaitu Blender untuk membuat objek kerangka tubuh manusia serta Unity3D untuk menghasilkan aplikasi kerangka tubuh manusia yang dikemas dalam bentuk aplikasi secara 3D. Metode Throw-Away Prototyping merupakan metode yang diterapkan pada penelitian ini. Penelitian ini menghasilkan aplikasi kerangka tubuh manusia sebagai media peraga terhadap 9 jenis tulang yang terdapat pada manusia yang berbasis Android menggunakan Animasi 3D yang menggunakan cardboard atau head mounted display